Technology Spawns Increased Activity In Mature Kansas Oil Industry

(Tech Connections Column, April 2003, American Oil and Gas Reporter)

Mention mature, and the Kansas oil and gas industry readily comes to mind, as might many other producing areas across the United States. Although mature, there are bright spots where technology is making an impact and spawning increased activity. Presentations at the Tertiary Oil Recovery Project’s 15th Oil Recovery Conference in mid-March in Wichita highlighted areas where technology is making a difference.

Since early 2001, Kansas operators have performed more than 150 larger-volume MARCIT^SM polymer gel treatments, primarily in the Arbuckle. Larger volumes, up to 4,000 barrels versus prior practice of a few hundred barrels, combined with the stable MARCIT technology are providing good results. Payout is typically less than six months. Although there is growing recognition that treatments may ultimately need to be repeated, there is still significant money being made between treatments.

Solid propellant stimulation treatments using GasGun^TM technology have also caught on in Kansas, with more than 50 operators treating 150 separate wells since early 2002. The formations most often being stimulated are the Arbuckle, followed by the Mississippian. Treatments can be performed in open or cased holes. With cased-hole treatments, one must ensure that there are adequate perforations to prevent casing damage.

Treatments may be done by themselves, but operators are often using them ahead of acid or hydraulic fracturing. Prepping the reservoir with a solid propellant stimulation treatment helps keep subsequent acid or frac jobs from going to water. PTTC’s North Mid-Continent Region is working with operators and service providers to build treatment databases for both the larger volume MARCIT gel polymer treatments and the GasGun stimulation treatments. Watch for progress during 2003.

Doing waterfloods right still offers significant potential in Kansas. One example is the PetroSantander Inc.-operated Morrow waterflood in Finney County. The waterflood, now a 20-acre five-spot pattern, was installed during a Department of Energy-supported Class I project. PetroSantander took over operations in 1997. The Morrow Sandstone being flooded is relatively homogenous with good communication (for the most part). Sandstones in this incised valley system are up to 70 feet thick, have good porosity (15-17 percent), and fair permeability (60-120 millidarcies). The six-mile long, one-third-mile wide accumulation is oriented east/west. There is negligible structure, with oil being stratigraphically trapped to north, south and east. Subtle faulting traps oil on the west.

Three-dimensional seismic amplitude data accurately imaged the incised valley system, whereas 2-D data had not. But the 3-D data was not helpful in characterizing sedimentary fill, so there have been several dry holes as shale-filled side valleys were drilled. Various trace inversions were attempted with no more success than with simple amplitude data.

By February 2003, the flood had recovered 8.6 million barrels. Ultimate recovery is estimated at 10.9 MMbbl, or 41 percent of the original oil in place, which represents about a 1.5-to-1 secondary-to-primary recovery ratio. Profitable development grew out of accurately imaging the incised valley system with 3-D seismic, aggressively drilling both the main accumulation and side valleys, and an aggressively implemented five-spot water flood pattern.

On the carbon dioxide flooding front, field work is now in progress on the long-awaited pilot flood of the Lansing-Kansas City C Zone in the Hall-Gurney Field. Changing conditions caused several project redesigns over the past couple years, but sustained commitment by TORP, the Kansas Geological Survey, and DOE are now bearing fruit. A nearby ethanol plant is supplying CO₂ for the four-year project. Although smaller than originally planned, it is still large enough to determine if waterflood residual oil can be mobilized. Success with CO₂ flooding could spawn significant activity in Kansas.

Dane Cantwell with Anadarko Petroleum Corporation provided insights about CO₂ flooding opportunities outside the Permian Basin. Among them is a major opportunity for Anadarko in the Salt Creek Field in Wyoming. A pilot should start there later this spring. A somewhat unique aspect of this flood is that, since the reservoir is shallow, the flood may not be fully miscible on the top of the structure. In broader comments, Cantwell observed that enhanced oil recovery projects, when one really looked at reserve development costs, could look quite favorable compared to other alternatives. Whether one agrees with this observation may depend on his perspective of probable oil and gas prices for the coming 5-10 years.

With human resources being scarce, Cantwell noted that it was essential to determine economic practicality of an EOR project before embarking on detailed design. For CO₂ flooding, a key screening factor is the proximity and availability of CO₂. Other key factors include secondary flooding performance (good waterfloods generally make good CO₂ floods), and performance estimates using screening models (CO₂ Prophet or Kinder Morgan models). Economic screening using various oil pricing scenarios is also critical.